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    <title>Document</title>
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    <div class="div">
        <p>111</p>
        <p>222</p>
        <p class="p3">333</p>
    </div>
</body>
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    let child = document.querySelector(".p3");
    let ret = parent.removeChild(child);
    console.dir(ret);
    parent.appendChild(ret);
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